causes condition has contributing genetic variation causes molecular phenotype Hemoglobin S Sickle Cell Disease-S/O-Arab Hemoglobin O-Arab HBB, GLU6VAL HBB, GLU121LYS SCD Genotype Hemoglobin Genotype S/O-Arab Request inclusion into relevant ontology Compound heterozygosity for the hemoglobin S (HBB Glu6Val) and hemoglobin O-Arab (HBB GluU121Lys) variants. Haemoglobin Genotype S/OArab S/O-Arab Genotype beta6Glu>Val/beta121Glu>Lys None Lancet. 2010 Dec 11;376(9757):2018-31. doi: 10.1016/S0140-6736(10)61029-X. Epub 2010 Dec 3.